<!--
    Author: wyb
    Create: 2021/11/23

    基于RSA和SHA-512的数字签名的实现过程:
	* 生成RSA要使用的公钥和私钥
	* 发送方用SHA-512算法生成明文的消息摘要
	* 发送方用RSA算法和私钥加密消息摘要
	* 发送方将明文、数字签名发送给接收方
	* 接收方对将加密后的消息摘要解密得到content1
	* 接收方用SHA-512生成明文的消息摘要content2
	* 将content1和content2对比, 如果是一样的说明签名有效, 否则签名无效

 -->
<!DOCTYPE html>
<html>
<head>
    <title>RSA数字签名实现</title>

    <!-- CSS代码 -->
    <style type="text/css">
        #container{
            width: 660px;
            margin: 0 auto;
        }
        #rsaform{
            margin-top: 30px;
            margin-bottom: 30px;
        }
    </style>

    <!--  sha512的实现代码	-->
    <!--  copy from: http://pajhome.org.uk/crypt/md5/sha512.html	-->
    <script>
        /*
         * A JavaScript implementation of the Secure Hash Algorithm, SHA-512, as defined
         * in FIPS 180-2
         * Version 2.2 Copyright Anonymous Contributor, Paul Johnston 2000 - 2009.
         * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
         * Distributed under the BSD License
         * See http://pajhome.org.uk/crypt/md5 for details.
         */

        /*
         * Configurable variables. You may need to tweak these to be compatible with
         * the server-side, but the defaults work in most cases.
         */
        var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */
        var b64pad  = ""; /* base-64 pad character. "=" for strict RFC compliance   */

        /*
         * These are the functions you'll usually want to call
         * They take string arguments and return either hex or base-64 encoded strings
         */
        function hex_sha512(s)    { return rstr2hex(rstr_sha512(str2rstr_utf8(s))); }
        function b64_sha512(s)    { return rstr2b64(rstr_sha512(str2rstr_utf8(s))); }
        function any_sha512(s, e) { return rstr2any(rstr_sha512(str2rstr_utf8(s)), e);}
        function hex_hmac_sha512(k, d)
        { return rstr2hex(rstr_hmac_sha512(str2rstr_utf8(k), str2rstr_utf8(d))); }
        function b64_hmac_sha512(k, d)
        { return rstr2b64(rstr_hmac_sha512(str2rstr_utf8(k), str2rstr_utf8(d))); }
        function any_hmac_sha512(k, d, e)
        { return rstr2any(rstr_hmac_sha512(str2rstr_utf8(k), str2rstr_utf8(d)), e);}

        /*
         * Perform a simple self-test to see if the VM is working
         */
        function sha512_vm_test()
        {
            return hex_sha512("abc").toLowerCase() ==
                "ddaf35a193617abacc417349ae20413112e6fa4e89a97ea20a9eeee64b55d39a" +
                "2192992a274fc1a836ba3c23a3feebbd454d4423643ce80e2a9ac94fa54ca49f";
        }

        /*
         * Calculate the SHA-512 of a raw string
         */
        function rstr_sha512(s)
        {
            return binb2rstr(binb_sha512(rstr2binb(s), s.length * 8));
        }

        /*
         * Calculate the HMAC-SHA-512 of a key and some data (raw strings)
         */
        function rstr_hmac_sha512(key, data)
        {
            var bkey = rstr2binb(key);
            if(bkey.length > 32) bkey = binb_sha512(bkey, key.length * 8);

            var ipad = Array(32), opad = Array(32);
            for(var i = 0; i < 32; i++)
            {
                ipad[i] = bkey[i] ^ 0x36363636;
                opad[i] = bkey[i] ^ 0x5C5C5C5C;
            }

            var hash = binb_sha512(ipad.concat(rstr2binb(data)), 1024 + data.length * 8);
            return binb2rstr(binb_sha512(opad.concat(hash), 1024 + 512));
        }

        /*
         * Convert a raw string to a hex string
         */
        function rstr2hex(input)
        {
            try { hexcase } catch(e) { hexcase=0; }
            var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
            var output = "";
            var x;
            for(var i = 0; i < input.length; i++)
            {
                x = input.charCodeAt(i);
                output += hex_tab.charAt((x >>> 4) & 0x0F)
                    +  hex_tab.charAt( x        & 0x0F);
            }
            return output;
        }

        /*
         * Convert a raw string to a base-64 string
         */
        function rstr2b64(input)
        {
            try { b64pad } catch(e) { b64pad=''; }
            var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
            var output = "";
            var len = input.length;
            for(var i = 0; i < len; i += 3)
            {
                var triplet = (input.charCodeAt(i) << 16)
                    | (i + 1 < len ? input.charCodeAt(i+1) << 8 : 0)
                    | (i + 2 < len ? input.charCodeAt(i+2)      : 0);
                for(var j = 0; j < 4; j++)
                {
                    if(i * 8 + j * 6 > input.length * 8) output += b64pad;
                    else output += tab.charAt((triplet >>> 6*(3-j)) & 0x3F);
                }
            }
            return output;
        }

        /*
         * Convert a raw string to an arbitrary string encoding
         */
        function rstr2any(input, encoding)
        {
            var divisor = encoding.length;
            var i, j, q, x, quotient;

            /* Convert to an array of 16-bit big-endian values, forming the dividend */
            var dividend = Array(Math.ceil(input.length / 2));
            for(i = 0; i < dividend.length; i++)
            {
                dividend[i] = (input.charCodeAt(i * 2) << 8) | input.charCodeAt(i * 2 + 1);
            }

            /*
             * Repeatedly perform a long division. The binary array forms the dividend,
             * the length of the encoding is the divisor. Once computed, the quotient
             * forms the dividend for the next step. All remainders are stored for later
             * use.
             */
            var full_length = Math.ceil(input.length * 8 /
                (Math.log(encoding.length) / Math.log(2)));
            var remainders = Array(full_length);
            for(j = 0; j < full_length; j++)
            {
                quotient = Array();
                x = 0;
                for(i = 0; i < dividend.length; i++)
                {
                    x = (x << 16) + dividend[i];
                    q = Math.floor(x / divisor);
                    x -= q * divisor;
                    if(quotient.length > 0 || q > 0)
                        quotient[quotient.length] = q;
                }
                remainders[j] = x;
                dividend = quotient;
            }

            /* Convert the remainders to the output string */
            var output = "";
            for(i = remainders.length - 1; i >= 0; i--)
                output += encoding.charAt(remainders[i]);

            return output;
        }

        /*
         * Encode a string as utf-8.
         * For efficiency, this assumes the input is valid utf-16.
         */
        function str2rstr_utf8(input)
        {
            var output = "";
            var i = -1;
            var x, y;

            while(++i < input.length)
            {
                /* Decode utf-16 surrogate pairs */
                x = input.charCodeAt(i);
                y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
                if(0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF)
                {
                    x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
                    i++;
                }

                /* Encode output as utf-8 */
                if(x <= 0x7F)
                    output += String.fromCharCode(x);
                else if(x <= 0x7FF)
                    output += String.fromCharCode(0xC0 | ((x >>> 6 ) & 0x1F),
                        0x80 | ( x         & 0x3F));
                else if(x <= 0xFFFF)
                    output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),
                        0x80 | ((x >>> 6 ) & 0x3F),
                        0x80 | ( x         & 0x3F));
                else if(x <= 0x1FFFFF)
                    output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),
                        0x80 | ((x >>> 12) & 0x3F),
                        0x80 | ((x >>> 6 ) & 0x3F),
                        0x80 | ( x         & 0x3F));
            }
            return output;
        }

        /*
         * Encode a string as utf-16
         */
        function str2rstr_utf16le(input)
        {
            var output = "";
            for(var i = 0; i < input.length; i++)
                output += String.fromCharCode( input.charCodeAt(i)        & 0xFF,
                    (input.charCodeAt(i) >>> 8) & 0xFF);
            return output;
        }

        function str2rstr_utf16be(input)
        {
            var output = "";
            for(var i = 0; i < input.length; i++)
                output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xFF,
                    input.charCodeAt(i)        & 0xFF);
            return output;
        }

        /*
         * Convert a raw string to an array of big-endian words
         * Characters >255 have their high-byte silently ignored.
         */
        function rstr2binb(input)
        {
            var output = Array(input.length >> 2);
            for(var i = 0; i < output.length; i++)
                output[i] = 0;
            for(var i = 0; i < input.length * 8; i += 8)
                output[i>>5] |= (input.charCodeAt(i / 8) & 0xFF) << (24 - i % 32);
            return output;
        }

        /*
         * Convert an array of big-endian words to a string
         */
        function binb2rstr(input)
        {
            var output = "";
            for(var i = 0; i < input.length * 32; i += 8)
                output += String.fromCharCode((input[i>>5] >>> (24 - i % 32)) & 0xFF);
            return output;
        }

        /*
         * Calculate the SHA-512 of an array of big-endian dwords, and a bit length
         */
        var sha512_k;
        function binb_sha512(x, len)
        {
            if(sha512_k == undefined)
            {
                //SHA512 constants
                sha512_k = new Array(
                    new int64(0x428a2f98, -685199838), new int64(0x71374491, 0x23ef65cd),
                    new int64(-1245643825, -330482897), new int64(-373957723, -2121671748),
                    new int64(0x3956c25b, -213338824), new int64(0x59f111f1, -1241133031),
                    new int64(-1841331548, -1357295717), new int64(-1424204075, -630357736),
                    new int64(-670586216, -1560083902), new int64(0x12835b01, 0x45706fbe),
                    new int64(0x243185be, 0x4ee4b28c), new int64(0x550c7dc3, -704662302),
                    new int64(0x72be5d74, -226784913), new int64(-2132889090, 0x3b1696b1),
                    new int64(-1680079193, 0x25c71235), new int64(-1046744716, -815192428),
                    new int64(-459576895, -1628353838), new int64(-272742522, 0x384f25e3),
                    new int64(0xfc19dc6, -1953704523), new int64(0x240ca1cc, 0x77ac9c65),
                    new int64(0x2de92c6f, 0x592b0275), new int64(0x4a7484aa, 0x6ea6e483),
                    new int64(0x5cb0a9dc, -1119749164), new int64(0x76f988da, -2096016459),
                    new int64(-1740746414, -295247957), new int64(-1473132947, 0x2db43210),
                    new int64(-1341970488, -1728372417), new int64(-1084653625, -1091629340),
                    new int64(-958395405, 0x3da88fc2), new int64(-710438585, -1828018395),
                    new int64(0x6ca6351, -536640913), new int64(0x14292967, 0xa0e6e70),
                    new int64(0x27b70a85, 0x46d22ffc), new int64(0x2e1b2138, 0x5c26c926),
                    new int64(0x4d2c6dfc, 0x5ac42aed), new int64(0x53380d13, -1651133473),
                    new int64(0x650a7354, -1951439906), new int64(0x766a0abb, 0x3c77b2a8),
                    new int64(-2117940946, 0x47edaee6), new int64(-1838011259, 0x1482353b),
                    new int64(-1564481375, 0x4cf10364), new int64(-1474664885, -1136513023),
                    new int64(-1035236496, -789014639), new int64(-949202525, 0x654be30),
                    new int64(-778901479, -688958952), new int64(-694614492, 0x5565a910),
                    new int64(-200395387, 0x5771202a), new int64(0x106aa070, 0x32bbd1b8),
                    new int64(0x19a4c116, -1194143544), new int64(0x1e376c08, 0x5141ab53),
                    new int64(0x2748774c, -544281703), new int64(0x34b0bcb5, -509917016),
                    new int64(0x391c0cb3, -976659869), new int64(0x4ed8aa4a, -482243893),
                    new int64(0x5b9cca4f, 0x7763e373), new int64(0x682e6ff3, -692930397),
                    new int64(0x748f82ee, 0x5defb2fc), new int64(0x78a5636f, 0x43172f60),
                    new int64(-2067236844, -1578062990), new int64(-1933114872, 0x1a6439ec),
                    new int64(-1866530822, 0x23631e28), new int64(-1538233109, -561857047),
                    new int64(-1090935817, -1295615723), new int64(-965641998, -479046869),
                    new int64(-903397682, -366583396), new int64(-779700025, 0x21c0c207),
                    new int64(-354779690, -840897762), new int64(-176337025, -294727304),
                    new int64(0x6f067aa, 0x72176fba), new int64(0xa637dc5, -1563912026),
                    new int64(0x113f9804, -1090974290), new int64(0x1b710b35, 0x131c471b),
                    new int64(0x28db77f5, 0x23047d84), new int64(0x32caab7b, 0x40c72493),
                    new int64(0x3c9ebe0a, 0x15c9bebc), new int64(0x431d67c4, -1676669620),
                    new int64(0x4cc5d4be, -885112138), new int64(0x597f299c, -60457430),
                    new int64(0x5fcb6fab, 0x3ad6faec), new int64(0x6c44198c, 0x4a475817));
            }

            //Initial hash values
            var H = new Array(
                new int64(0x6a09e667, -205731576),
                new int64(-1150833019, -2067093701),
                new int64(0x3c6ef372, -23791573),
                new int64(-1521486534, 0x5f1d36f1),
                new int64(0x510e527f, -1377402159),
                new int64(-1694144372, 0x2b3e6c1f),
                new int64(0x1f83d9ab, -79577749),
                new int64(0x5be0cd19, 0x137e2179));

            var T1 = new int64(0, 0),
                T2 = new int64(0, 0),
                a = new int64(0,0),
                b = new int64(0,0),
                c = new int64(0,0),
                d = new int64(0,0),
                e = new int64(0,0),
                f = new int64(0,0),
                g = new int64(0,0),
                h = new int64(0,0),
                //Temporary variables not specified by the document
                s0 = new int64(0, 0),
                s1 = new int64(0, 0),
                Ch = new int64(0, 0),
                Maj = new int64(0, 0),
                r1 = new int64(0, 0),
                r2 = new int64(0, 0),
                r3 = new int64(0, 0);
            var j, i;
            var W = new Array(80);
            for(i=0; i<80; i++)
                W[i] = new int64(0, 0);

            // append padding to the source string. The format is described in the FIPS.
            x[len >> 5] |= 0x80 << (24 - (len & 0x1f));
            x[((len + 128 >> 10)<< 5) + 31] = len;

            for(i = 0; i<x.length; i+=32) //32 dwords is the block size
            {
                int64copy(a, H[0]);
                int64copy(b, H[1]);
                int64copy(c, H[2]);
                int64copy(d, H[3]);
                int64copy(e, H[4]);
                int64copy(f, H[5]);
                int64copy(g, H[6]);
                int64copy(h, H[7]);

                for(j=0; j<16; j++)
                {
                    W[j].h = x[i + 2*j];
                    W[j].l = x[i + 2*j + 1];
                }

                for(j=16; j<80; j++)
                {
                    //sigma1
                    int64rrot(r1, W[j-2], 19);
                    int64revrrot(r2, W[j-2], 29);
                    int64shr(r3, W[j-2], 6);
                    s1.l = r1.l ^ r2.l ^ r3.l;
                    s1.h = r1.h ^ r2.h ^ r3.h;
                    //sigma0
                    int64rrot(r1, W[j-15], 1);
                    int64rrot(r2, W[j-15], 8);
                    int64shr(r3, W[j-15], 7);
                    s0.l = r1.l ^ r2.l ^ r3.l;
                    s0.h = r1.h ^ r2.h ^ r3.h;

                    int64add4(W[j], s1, W[j-7], s0, W[j-16]);
                }

                for(j = 0; j < 80; j++)
                {
                    //Ch
                    Ch.l = (e.l & f.l) ^ (~e.l & g.l);
                    Ch.h = (e.h & f.h) ^ (~e.h & g.h);

                    //Sigma1
                    int64rrot(r1, e, 14);
                    int64rrot(r2, e, 18);
                    int64revrrot(r3, e, 9);
                    s1.l = r1.l ^ r2.l ^ r3.l;
                    s1.h = r1.h ^ r2.h ^ r3.h;

                    //Sigma0
                    int64rrot(r1, a, 28);
                    int64revrrot(r2, a, 2);
                    int64revrrot(r3, a, 7);
                    s0.l = r1.l ^ r2.l ^ r3.l;
                    s0.h = r1.h ^ r2.h ^ r3.h;

                    //Maj
                    Maj.l = (a.l & b.l) ^ (a.l & c.l) ^ (b.l & c.l);
                    Maj.h = (a.h & b.h) ^ (a.h & c.h) ^ (b.h & c.h);

                    int64add5(T1, h, s1, Ch, sha512_k[j], W[j]);
                    int64add(T2, s0, Maj);

                    int64copy(h, g);
                    int64copy(g, f);
                    int64copy(f, e);
                    int64add(e, d, T1);
                    int64copy(d, c);
                    int64copy(c, b);
                    int64copy(b, a);
                    int64add(a, T1, T2);
                }
                int64add(H[0], H[0], a);
                int64add(H[1], H[1], b);
                int64add(H[2], H[2], c);
                int64add(H[3], H[3], d);
                int64add(H[4], H[4], e);
                int64add(H[5], H[5], f);
                int64add(H[6], H[6], g);
                int64add(H[7], H[7], h);
            }

            //represent the hash as an array of 32-bit dwords
            var hash = new Array(16);
            for(i=0; i<8; i++)
            {
                hash[2*i] = H[i].h;
                hash[2*i + 1] = H[i].l;
            }
            return hash;
        }

        //A constructor for 64-bit numbers
        function int64(h, l)
        {
            this.h = h;
            this.l = l;
            //this.toString = int64toString;
        }

        //Copies src into dst, assuming both are 64-bit numbers
        function int64copy(dst, src)
        {
            dst.h = src.h;
            dst.l = src.l;
        }

        //Right-rotates a 64-bit number by shift
        //Won't handle cases of shift>=32
        //The function revrrot() is for that
        function int64rrot(dst, x, shift)
        {
            dst.l = (x.l >>> shift) | (x.h << (32-shift));
            dst.h = (x.h >>> shift) | (x.l << (32-shift));
        }

        //Reverses the dwords of the source and then rotates right by shift.
        //This is equivalent to rotation by 32+shift
        function int64revrrot(dst, x, shift)
        {
            dst.l = (x.h >>> shift) | (x.l << (32-shift));
            dst.h = (x.l >>> shift) | (x.h << (32-shift));
        }

        //Bitwise-shifts right a 64-bit number by shift
        //Won't handle shift>=32, but it's never needed in SHA512
        function int64shr(dst, x, shift)
        {
            dst.l = (x.l >>> shift) | (x.h << (32-shift));
            dst.h = (x.h >>> shift);
        }

        //Adds two 64-bit numbers
        //Like the original implementation, does not rely on 32-bit operations
        function int64add(dst, x, y)
        {
            var w0 = (x.l & 0xffff) + (y.l & 0xffff);
            var w1 = (x.l >>> 16) + (y.l >>> 16) + (w0 >>> 16);
            var w2 = (x.h & 0xffff) + (y.h & 0xffff) + (w1 >>> 16);
            var w3 = (x.h >>> 16) + (y.h >>> 16) + (w2 >>> 16);
            dst.l = (w0 & 0xffff) | (w1 << 16);
            dst.h = (w2 & 0xffff) | (w3 << 16);
        }

        //Same, except with 4 addends. Works faster than adding them one by one.
        function int64add4(dst, a, b, c, d)
        {
            var w0 = (a.l & 0xffff) + (b.l & 0xffff) + (c.l & 0xffff) + (d.l & 0xffff);
            var w1 = (a.l >>> 16) + (b.l >>> 16) + (c.l >>> 16) + (d.l >>> 16) + (w0 >>> 16);
            var w2 = (a.h & 0xffff) + (b.h & 0xffff) + (c.h & 0xffff) + (d.h & 0xffff) + (w1 >>> 16);
            var w3 = (a.h >>> 16) + (b.h >>> 16) + (c.h >>> 16) + (d.h >>> 16) + (w2 >>> 16);
            dst.l = (w0 & 0xffff) | (w1 << 16);
            dst.h = (w2 & 0xffff) | (w3 << 16);
        }

        //Same, except with 5 addends
        function int64add5(dst, a, b, c, d, e)
        {
            var w0 = (a.l & 0xffff) + (b.l & 0xffff) + (c.l & 0xffff) + (d.l & 0xffff) + (e.l & 0xffff);
            var w1 = (a.l >>> 16) + (b.l >>> 16) + (c.l >>> 16) + (d.l >>> 16) + (e.l >>> 16) + (w0 >>> 16);
            var w2 = (a.h & 0xffff) + (b.h & 0xffff) + (c.h & 0xffff) + (d.h & 0xffff) + (e.h & 0xffff) + (w1 >>> 16);
            var w3 = (a.h >>> 16) + (b.h >>> 16) + (c.h >>> 16) + (d.h >>> 16) + (e.h >>> 16) + (w2 >>> 16);
            dst.l = (w0 & 0xffff) | (w1 << 16);
            dst.h = (w2 & 0xffff) | (w3 << 16);
        }
    </script>
    <!--  验证sha512: https://crypot.51strive.com/sha512.html	-->


    <!-- RSA数字签名的核心代码 -->
    <script type="text/javascript">

        // test sha512算法
        // alert(hex_sha512("test"));

        // 密文序列
        let emsg;

        window.onload = function init() {
            // 直接初始化n e1 e2
            // <!-- n e1 e2的一个例子：3599、3031、31 -->
            document.getElementById("n").value = 3599;
            document.getElementById("e1").value = 3031;
            document.getElementById("e2").value = 31;
        }

        // 解密并解码处理
        function decode(n, d, emsg) {
            // 逐位计算每一位解密后的信息
            let lens = emsg.length
            let str = Array(lens)
            for (let i=0; i<lens; i++){
                // 解密
                str[i] = rsamath(n, d, emsg[i])
                console.log("rsa解密后得到的每一位: ", str[i])
                str[i] = String.fromCharCode(parseInt(str[i]))	// 将BigInt转换成int再转换成char
            }

            return str;

        }

        // 加密并编码处理，因为RSA算法依据的是大整数求解问题，所以需要将消息编码后计算
        function encode(n, e, str) {
            let lens = str.length;
            let emsg = Array(lens);
            for (let i=0; i<lens; i++){
                // 将每一位转换成ascii码
                let ascii = str.charAt(i).charCodeAt(0);
                // 对ascii码加密
                emsg[i] = rsamath(n, e, ascii);
            }

            return emsg;
        }

        // 将数据转换成JavaScript中的BigInt类型
        function rsamath(n, e, msg){
            return rsamathCore(BigInt(n), BigInt(e), BigInt(msg))
            // return rsamathCore(n, e, msg) => 这样不行 必须转换成BigInt 否则会有溢出bug
        }

        // rsa核心代码
        function rsamathCore(n, e, msg) {
            return msg ** e % n
        }

        // 获得签名
        function getDigitSignature() {
            // 获取原文
            let plaintext = document.getElementById("plaintext").value;
            // 获取n e1
            let n = document.getElementById("n").value;
            let e1 = document.getElementById("e1").value;

            // 计算原文的摘要并将原文摘要显示到获得消息摘要后面
            let digest = hex_sha512(plaintext);
            document.getElementById("showDigest").value = digest;

            // 对摘要用RSA进行加密获得密文并显示到获得密文后面
            emsg = encode(n, e1, digest);
            // 将密文转换成字符串
            let encodeRes = "";
            for (let i=0; i<emsg.length; i++){
                encodeRes += emsg[i];
            }
            document.getElementById("showSecret").value = encodeRes;

        }

        // 验证签名
        function verifyDigitSignature(){
            // 获取原文
            let plaintext = document.getElementById("plaintext").value;

            // 获取n e2
            let n = document.getElementById("n").value;
            let e2 = document.getElementById("e2").value;

            // 解密得到摘要然后和原文生成的摘要对比
            // 解密得到摘要
            let decodeDigest = decode(n, e2, emsg);
            let decodeRes = "";
            for (let i=0; i<decodeDigest.length; i++){
                decodeRes += decodeDigest[i];
            }
            // alert(decodeRes)
            document.getElementById("digestVerification").value = decodeRes

            // 通过原文生成摘要
            let digest = hex_sha512(plaintext);
            // 将原文生成的摘要与解密得到的摘要进行对比
            if (digest === decodeRes){
                alert("验证成功")
            } else{
                alert("验证失败")
            }

        }

        // 重置
        function retry() {
            // 清空输入的原文和输出的结果
            document.getElementById("plaintext").value = ""
            document.getElementById("showDigest").value = ""
            document.getElementById("showSecret").value = ""
            document.getElementById("digestVerification").value = ""
        }


    </script>

    <!-- 最新版本的 Bootstrap 核心 CSS 文件 -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css" integrity="sha384-HSMxcRTRxnN+Bdg0JdbxYKrThecOKuH5zCYotlSAcp1+c8xmyTe9GYg1l9a69psu" crossorigin="anonymous">

</head>
<body>

<div id="container">
    <!-- n e1 e2的一个例子：3599、3031、31 -->
    <div id="rsaform">
        <form class="form-horizontal" role="form">
            <div class="form-group">
                <label for="plaintext" class="col-sm-2 control-label">明文</label>
                <div class="col-sm-10">
                    <input type="text" class="form-control" id="plaintext" placeholder="请输入明文">
                </div>
            </div>
            <div class="form-group">
                <label for="n" class="col-sm-1 control-label">n</label>
                <div class="col-sm-3">
                    <input type="text" class="form-control" id="n" placeholder="请输入n">
                </div>
                <label for="e1" class="col-sm-1 control-label">e1</label>
                <div class="col-sm-3">
                    <input type="text" class="form-control" id="e1" placeholder="请输入e1">
                </div>
                <label for="e2" class="col-sm-1 control-label">e2</label>
                <div class="col-sm-3">
                    <input type="text" class="form-control" id="e2" placeholder="请输入e2">
                </div>
            </div>

            <div class="form-group">
                <label for="showDigest" class="col-sm-2 control-label">获得消息摘要</label>
                <div class="col-sm-10">
                    <input type="text" class="form-control" id="showDigest" placeholder="这里放SHA512生成的消息摘要" disabled>
                </div>
            </div>

            <div class="form-group">
                <label for="showSecret" class="col-sm-2 control-label">获得密文</label>
                <div class="col-sm-10">
                    <input type="text" class="form-control" id="showSecret"  placeholder="这里放消息摘要经过RSA加密后的密文(即签名)" disabled>
                </div>
            </div>

            <div class="form-group">
                <label for="digestVerification" class="col-sm-2 control-label">验证消息摘要</label>
                <div class="col-sm-10">
                    <input type="text" class="form-control" id="digestVerification"  placeholder="这里放对密文经过RSA解密后的消息摘要" disabled>
                </div>
            </div>

            <div class="form-group">
                <div class="col-sm-offset-2 col-sm-10">
                    <button onclick="getDigitSignature()" type="button" class="btn btn-default">获得签名</button>
                    <button onclick="verifyDigitSignature()" type="button" class="btn btn-default">验证签名</button>
                    <button onclick="retry()" type="button" class="btn btn-default">Retry</button>
                </div>
            </div>
        </form>
    </div>

</div>




</body>
</html>